1. Field of the Invention
The present invention relates to a system for connecting the frame members of a picture frame, and more particular to such a system which is particularly adapted to accommodate irregularities in the frame members.
2. Background Art
Picture frames are commonly assembled from four elongate frame members having connecting mitred end portions. A traditional method of securing the frame members to one another is to apply glue to the mitred end surfaces and clamp the frame members together until the bonding agent holds the members securely to one another. However, this is a somewhat time consuming operation, and generally specialized equipment is required to utilize this method effectively.
Accordingly, there have been various approaches in the prior art to use mechanical connecting devices to join the frame members together. In general, some sort of recesses or slots are formed in the adjacent end portions of two frame members, and a connecting device of a configuration generally matching the recesses is placed into the adjacent recesses in a manner to hold those end portions together.
A search of the U.S. patents has revealed a number of such devices, these being the following:
U.S. Pat. No. 4,509,882--Lautenschalger shows such a connecting device having a dumbbell shaped configuration. One portion of the connecting device has an eccentric section, so that rotation of that portion causes the two parts of the fastener to be drawn together to make a tight joint.
U.S. Pat. No. 4,493,583--Wallace shows a connector with two leg portions which meet each other at a right angle, and two end enlargements. This connector fits into similarly shaped grooves in the end portions of the frames. The lower edge portions of this connector have the side surfaces tapered inwardly.
U.S. Pat. No. 4,275,932--Bowen et al shows a connector having an "H" or "I" configuration. The middle portion of the fastener has a box like configuration, and there is a tightening screw which has the effect of drawing the two end fastening elements together to make a tighter connection.
U.S. Pat. No. 3,425,721--Agee shows a dumbbell shaped fastener for joining the mitred corners. The two sections of the matching recess slant away from each other in a downward direction so that insertion of the connector draws the frame members more closely to one another.
U.S. Pat. No. 1,537,678--Jensen discloses an "I" shaped joining device. This device is constructed of flanged channel shaped members.
U.S. Pat. No. 1,165,155--Cordes discloses another form of a dumbbell shaped joining device.
U.S. Pat. No. 1,061,855--Lobo shows another connecting device having a dumbbell configuration, where the end portions of the connector are rolled portions.
U.S. Pat. No. 497,915--Fulghum et al shows a connector where there is a dumbbell shape, with the end portions of the connector fitting into tapered recesses.
U.S. Pat. No. 111,128--Linscott discloses another joining device where there are end enlargements having a slanted configuration.
It is an object of the present invention to provide a fastening device particularly adapted for joining framing members of a picture frame to one another, with the fastening device being well adapted to accommodate irregularigies and/or deviations in the frame members, for example, where the frame members might be slightly warped along the lengthwise axis of the frame member.